The speaker begins by calling to a butterfly, urging the warm, damp summer air to carry it up into the sun. From there the poem drifts into a hidden valley of birches, where "wonders" seem to wait. Soon the butterfly feels like more than an insect. It becomes something close to inspiration, the quiet presence that fills the "white blank pages" and is known "of you alone."
The speaker feels tender and hopeful, with a touch of nervousness in the "trembling fingertips." Writing is approached cautiously, almost like climbing a slope. Then something breaks open: light enters, and the "rules of language" flutter off like the butterfly itself. The ending is joyful and physical, as a "blaze of sudden flowers" plays on the speaker's tongue. The mood is airy and sensual, a feeling of words arriving freely once the speaker stops forcing them. The slashes and gaps in the lines mimic that fluttering, hesitant movement.